This invention is an improvement of an internal combustion engine which is encapsulated in a soundproof manner and which has an oil pan connected with the engine block by means of a sound dampening intermediate layer situated between circumferential mounting faces of the engine block and the oil pan. The oil pan is also connected with sound dampening means to a lower terminal zone of the capsule. Such an arrangement is disclosed in United States patent application Ser. No. 952,445, filed Oct. 18, 1978 and entitled SOUND INSULATED INTERNAL COMBUSTION ENGINE.